1. Field of Invention
The invention relates to a traffic information output device for supplying a user with pieces of traffic information and a traffic information distribution device/method for distributing pieces of traffic information. More specifically, the invention relates to a traffic information output device or the like which is capable of supplying a user with pieces of traffic information that have been effectively synthesized.
2. Description of Related Art
In general, as disclosed in Japanese Patent Laid-Open Application No. 10-47979, there is known a navigation system wherein pieces of traffic information are supplied from a traffic information center by means of FM broadcast or a radio/optical beacon and wherein the supplied pieces of traffic information are displayed on a display monitor through an onboard navigation device. The traffic information center separately collects pieces of traffic information on predetermined regions and transmits the collected pieces of traffic information by means of FM broadcast or the radio/optical beacon. After a vehicle has entered a certain one of the predetermined regions, the onboard navigation device acquires the pieces of traffic information on that region at intervals of a certain period. Thus, this navigation system makes it possible to suitably supply the user with pieces of traffic information on each of the regions.
Due to rapid progress and development of portable terminals such as cellular phones and personal handyphone system (PHS), as a method of acquiring pieces of traffic information, it has become contemplable to provide a system that requests transmission of a certain piece of traffic information on a desired region from the side of a portable terminal capable of outputting pieces of traffic information, that distributes the piece of traffic information on that region from the traffic information center to the side of the portable terminal in response to the request, and that causes the portable terminal to receive the piece of traffic information supplied from the traffic information center. According to this system, the user carries the portable terminal, whereby it becomes possible for the user to acquire pieces of traffic information on an arbitrary one of different regions.
However, while pieces of traffic information on an arbitrary one of different regions can thus be acquired, the pieces of traffic information are actually pieces of information consisting of many pieces of information such as traffic jam information, regulation information, parking space information, service area information, which are each related to a certain region. It is impossible to request transmission of only a desired piece of information (e.g., parking space information) selected from these pieces of information from the side of the portable terminal. As a result, pieces of information that are not desired by the user are displayed on the side of the portable terminal, and the user is not guaranteed of good visibility.
Further, while pieces of traffic information on an extensive range can be acquired, pieces of traffic information on the extensive region which are enormous in amount are displayed on a display screen on the side of the portable terminal with high density. Thus, the state of display becomes complicated. Because data to be distributed are enormous in size, the time required for transmission of the data and the time required for the processing of the data for display are increased. This increase in processing time subsequently leads to an increase in the communication cost as well as a deterioration in responsive characteristics.